The present invention relates to a new and improved construction of gear pump.
In its more particular aspects, the gear pump of the present development is of the type comprising a pump housing having an inlet and an outlet and two meshing pumping gear wheels enclosed by the pump housing. There are also provided a transmission housing including a base arrangement and two meshing auxiliary gear wheels enclosed in the transmission housing. The pump housing and the transmission housing define a common primary axis. An end bearing plate is disposed on the side of the transmission housing which is remote from the pump housing and an intermediate bearing plate is disposed intermediate the pump housing and the transmission housing. Two shafts are arranged symmetrically in respect of the primary axis and are rotatably journaled in the end bearing plate and in the intermediate bearing plate. One of the two shafts forms a driving shaft. Each of the two shafts carries a respective one of the pumping gear wheels and one of the auxiliary gear wheels and an outwardly protruding shaft stud or journal is provided at the driving shaft.
In a gear pump as known, for example, from U.S. Pat. No. 4,225,296, the end bearing plate is formed in one-piece with the transmission housing and is provided with two bearing bores, in each of which one of the two shafts is journaled. Consequently, the arrangement of the two shafts with respect to the transmission housing is established once and for all. The pump housing is bolted to the transmission housing through the intermediate bearing plate and is also designed such that the once established mutual positional correlation of pump housing and transmission housing thereafter no longer can be changed. Therefore, the suction and pressure lines intended to be connected to such prior art gear pump have to be adapted to the installation position of the gear pump as governed by the position of the base arrangement of the transmission housing.